Assessment Notes

RATHER CONSIDER DD

1 site x 10 potential sites x 2 genets x 10 ramets = 200 (Vulnerable)

Taxonomic notes

Described by Buyck, Adamčik & Lewis in 2008, Russula texensis is in section Xerampelinae, has a purplish reddish and mottled cap, a fishy odor and develops greenish color with Iron Sulfate. It can be separated from other similar colored Russulas by its fishy odor and reaction with Iron Sulfate

Why suggested for a Global Red List Assessment?

A very rare species only known from one location in East Texas. Continued collecting since 2008 has not found other populations. Previous studies by Thiers (1950-1963) had no reports of Russula in the Xerampelinae group from Texas.

Geographic range

Only known from a single specimen, Bleakwood, Newton Co., Texas on Lewis property.

Population and Trends

1 site x 10 potential sites x 2 genets x 10 ramets = 200 (Vulnerable)
Repeated collecting by Lewis, Buyck and Ovrebo since 2008 near the holotype site has not observed more specimens. The Gulf States Mycological Society annual summer forays in similar sites in Louisiana and Mississippi have not found other populations. Thiers (1950-1963) had no reports of Russula in the Xeramphelinae group from Texas, Louisiana, Mississippi, Alabama and Florida.

Threats

Russula texensis is a mycorrhizal fungus species so it is dependent on living host trees for population viability. This mutually beneficial symbiotic association between fungus and plant host roots conveys numerous critical advantages for plant host survival. Mycorrhizal fungi are essentially the uptake organs for many nutrients i.e., nitrogen, phosphorus, numerous micronutrients, i.e., boron, selenium, copper, and plays a major role in uptake of water. Both the fungus and the plant host does not exist in nature without each other. Severe drought and hurricane damage may impact populations due to tree mortality and forest destruction. Also the influx of invasive species such as Chinese Tallow-tree (Sapium sebiferum) and Chinese Privet (Ligustrum sinense ) has influenced the overall ecology of the region. Another problem is destruction of plants and soil by feral hogs.

Invasive non-native/alien species/diseases

Conservation Actions

The property where the population is located is under study for a conservation easement, which will protect habitat from logging and commercial development. Similar ecological sites are located nearby (within 25 miles) in Big Thicket National Preserve (National Park Service), which is a federally protected area.

Site/area protection

Research needed

In the gulf coast of North America, where Russula texensis is found, there are numerous groups of amateur mycologists. Members of these groups can be recruited and instructed where to find and how to identify R. texensis so they can target this species during forays. Data from amateur mycologists can be critical to define R. texensis population size, distribution and trends, as well as its ectomycorrhizal associations. Annual forays by the Gulf States Mycological Society continues to search for other populations. Lewis continues to monitor areas at holotype site and areas in Big Thicket National Preserve.